1. Field of the Invention
The present invention is directed to a method for operating a hearing aid system and to a hearing aid system having at least two hearing aid devices between which a signal path is provided and having at least one signal-processing unit that is adaptable to different hearing situations.
2. Description of the Prior Art
In many instances, a hearing impairment affects both ears; so the hearing impaired person should be supplied with hearing aids in both ears (binaurally). Modern hearing aids have signal-processing algorithms that automatically vary the parameters of the hearing aids dependent on the hearing situation. These variations are directed to the switching between microphone modes (omnidirectional or various directional microphone modes) as well as the effect of various stages of the signal processing thereby allowing adaptation to the hearing situation. In binaural coverage, the hearing situation at both ears is evaluated. However, the evaluation can lead to slightly divergent results due to slightly different acoustic fields at both ears. In the inside of a passenger vehicle, for example, the acoustic levels measured at the two ears can significantly differ; a definitive resolution as to the spatial arrangement of the noise sources also fluctuates greatly. In the case of such a separate evaluation, thus, different settings of the hearing aids can be avoided only with difficulty.
U.S. Pat. No. 5,604,812 discloses a hearing aid device that has a signal analysis unit for the automatic switching between various hearing programs, the signal analysis unit recognizing the current hearing situation and selecting a suitable hearing program. A disadvantage is that the automatic recognition of the hearing situation in the case of a system having two hearing aid devices can lead to different results and, thus, to the operation of the hearing aid devices in different hearing programs.
PCT Application 00/00001 discloses a method for the operation of binaural hearing aids, each of which can be switched in situ into at least two transmission modes from the microphone to the output transducer arrangement (hearing programs). The active hearing programs of the hearing aids are manually or automatically synchronized to prescribed or prescribable program pairings via a wireless connection between the hearing aids. A disadvantage of this known method is that the momentary hearing situation is not correctly recognized, and one of the hearing aids or both hearing aids are operated in a incorrect hearing program.
U.S. Pat. No. 5,757,932 discloses a hearing aid system with at least two hearing aids for binaural coverage of a hearing aid user wherein transmission of acoustic signals between the two hearing aids is provided. A disadvantage of this known hearing aid system is the high quantity of data transmitted between the two hearing aids.